Vehicles include seatbelts for each of the seats onboard. The seatbelt includes webbing that, when the seatbelt is buckled, stretches across an occupant of the seat. An anchor attaches one end of the webbing to a seat frame. The other end of the webbing feeds into a retractor, which includes a spool that pays out and retracts the webbing. A clip slides freely along the webbing and, when engaged with a buckle, divides the webbing into a lap band and a shoulder band. The seatbelt is typically a three-point harness, meaning that the webbing is attached at three points around the occupant when fastened: the anchor, the retractor, and the buckle.
In some vehicles, a subset of the seats (typically rear seats) include automatic locking mechanisms for use when installing a child seat for a small child or infant. When the webbing is fully paid out, the retractor switches to an automatic locking mode, in which the webbing may be retracted but not paid out. The webbing thus securely holds the child seat in the seat.